Kniffin and Hanks used data from the Survey of Earned Doctorates (conducted by the National Science Foundation), based on data from all people who earned PhDs in the U.S.A. between July 1 2009 and June 30 2010 (c. 43,000 people). Apparently, 14,000 people (32.5 %) reported that their doctoral work spanned academic boundaries

Two of their main findings are: (i) individuals who complete an interdisciplinary dissertation display short-term income risk, since they tend to earn nearly $1,700 less in the year after graduation; and (ii) the probability that non-citizens pursue interdisciplinary dissertation work is 4.7% higher when compared with U.S. citizens. Sadly, but not unexpectedly, women tend to earn less compared to men upon completion of the doctorate. Perhaps less expectedly, European American individuals also earn less in their first year after graduation than those in other racial groups.

In the regression models, adjusting for all other factors, the "influence of interdisciplinary research upon salary" was positive for Computer Sciences & Mathematics as well as for Health Sciences, but was negative for Biological Sciences. However, the "influence of interdisciplinary research upon employment as postdoctoral researcher" was negative for Computer Sciences & Mathematics as well as for Health Sciences, but was positive for Biological Sciences.